But choppy financial markets, trade tensions and fears of an economic slowdown hampered deal makers when they returned from summer vacation. It was still a good year and is set to go down as the third-busiest ever for M&A, trailing only 2007 and 2015, with more than $3.8 trillion in announced deals.

It was also a good year for the bankers and lawyers who helped arrange all those corporate marriages, for which they reap fees that can run into the tens of millions of dollars. The Wall Street Journal spoke to some of those who landed the biggest fish and asked, among other things, what's in store for 2019.

Mega Mergers

Roger Altman, founder and senior chairman at EvercoreMr. Altman had a seat at the table for a chess match between some of media's most powerful players, advising Comcast Corp. on its $38.7 billion acquisition of Sky PLC. Comcast outbid 21st Century Fox Inc. —itself involved in a deal with Walt Disney Co. — ending a monthslong takeover battle. "The three or four most complicated transactions I ever worked on all occurred in the last two years," says the longtime deal maker. Mr. Altman remains upbeat, but acknowledges that declines in the stock prices of advisory firms such as Evercore and Lazard suggest investors are less certain. Either way, the proliferation of thorny deals is here to stay, he says.

Frank Aquila, partner at Sullivan & Cromwell LLPMr. Aquila, who has advised corporate clients in consumer, health-care and other industries, helped arrange one of the year's largest energy deals, working with Andeavor Corp. on its $23 billion sale to Marathon Petroleum Corp., announced in April. "I thought we were going to see more activity than we did in the second half of the year," he says. But Mr. Aquila says he isn't fretting about 2019, in part because M&A is part of the day-to-day decision-making at big companies now. "I don't think we're going to go through the type of boom and bust we've seen in prior periods," he says.

Scott Barshay, global head of M&A at Paul, Weiss, Rifkind, Wharton & Garrison LLPWhen the powerhouse corporate lawyer left white-shoe firm Cravath Swaine & Moore LLP in 2016, all eyes were on whether members of Cravath's storied stable of clients would follow. In October, when International Business Machines Corp. , a decadeslong Cravath client, tapped Mr. Barshay to do its largest deal ever—the $37 billion purchase of Red Hat Inc.—he proved that even some of the stickiest Cravath clients remained loyal to him. He seemed to find a role on one big deal after another in 2018 including the planned marriage of Harris Corp. and L3 Technologies Inc. On the year, Mr. Barshay advised on more than $300 billion in transactions. "2018 was a year of big deals," he says.

George Boutros, CEO of Qatalyst Partners
Technology was 2018's busiest sector for deal making. Mr. Boutros was in the middle of much of the action, including selling CA Technologies to Broadcom Inc. for $19 billion. Qatalyst also sold market-analytics startup Qualtrics International Inc. to SAP SE for $8 billion. Mr. Boutros is bullish: "The drivers for M&A are there, and I think there will be a lot of activity in software, barring extreme volatility."

Chris Gallea, formerly of JPMorgan, now vice chairman of investment banking atGoldman Sachs GroupInc.Mr. Gallea hit the ground running when he joined Goldman from JPMorgan Chase & Co. in May, helping ink L3's merger with Harris—the largest-ever defense-industry merger—just months into his new role. In November, Goldman was named as an adviser on United Technologies Corp.'s giant, three-way breakup. Over the past year, Goldman has hired more than a dozen high-ranking dealmakers. The industrial assignments show the hiring spree is already starting to pay off. Conglomerates are narrowing their focus to one or two fields, a trend that Mr. Gallea predicts will generate more deal activity. "CEOs are asking themselves ‘what are the businesses we should not be in and how do we exit them in a smart way,'" he says.

Gregg Lemkau, co-head of investment banking at GoldmanMr. Lemkau put his 26 years of experience at Wall Street's No. 1 merger adviser to use in Dell Technologies Inc.'s $24 billion buyout of shares that track its VMware Inc. cloud operation. Mr. Lemkau played an important role bridging differences between Dell and hedge funds that argued its initial proposal was too stingy. Eventually Dell sweetened the offer, part of a plan to take the PC and data-storage giant public again, and the investors dropped their opposition. (The new Dell shares started trading Friday.) The year "was phenomenal—for three quarters," says Mr. Lemkau, who expresses hope that in the new year executives will refocus on strategic priorities and spur a return to increased deal activity. "CEOs feel really good about their fundamental business outlook and growth prospects," he says.

Kurt Simon, ex-JPMorgan now co-chair of global technology, media and telecommunications at GoldmanBefore joining Goldman from JPMorgan in November, Mr. Simon advised Disney on its $71 billion deal to buy a big chunk of 21st Century Fox. The deal, one of the largest in recent years, was contentious and involved a bidding war between Disney and Comcast. Mr. Simon also advised Sprint Corp. on its sale to T-Mobile US Inc., which many deal watchers thought would never actually happen. (The deal still requires regulatory approval.) In 2018, M&A was done "at a feverish pace," Mr. Simon says. "But if the volatility persists, matching 2018's pace may prove to be a challenge."

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